This invention is in the field of non-invasive spectral analysis of analytes in tissues and relates more particularly to a device which may be used with a non-invasive monitoring system used for determining concentrations of various blood components.
Non-invasive devices exist which are used externally to measure either the concentration of the constituent in gases admitted by the body or the concentrations contained in a patient""s body part, typically a finger. U.S. Pat. No. 5,429,128 describes a finger receptor which receives a finger of a user and is for use with a non-invasive monitoring device. U.S. Pat. No. 5,361,758 describes such a monitoring device.
During the course of using a monitoring device which is operatively coupled to a finger receptor, many uses of the receptor and the monitoring device will, with time, result in variations in readings due to internal drift and other variable aspects of such monitoring devices. Accordingly, it is desirable to have a means to rapidly and easily check the precision and accuracy of such a monitoring device.
The present inventors have developed a device shaped to fit a receptor which is operatively connected to a non-invasive monitoring device, which device is useful in monitoring the precision and accuracy of the non-invasive monitoring device and which permits photometric correction of the instrument.
In its broad aspect, the invention provides a method and a device made of materials for carrying out the method which reproduce absorption spectra associated with various body parts when such parts are subjected to spectral determination. A device according to the present invention is made of a material that exhibits the same light scattering and absorbance characteristics as a body part, preferably of an earlobe, lip, fold of skin or finger, most preferably, a finger.
According to one embodiment of the present invention, there is provided an artificial member, which mimics the absorbance spectrum of a body part and includes the spectral components of blood analytes comprising a light scattering and reflecting material, which member has a chamber portion comprising one or more chambers, said member configured to be reproducibly received in a measuring receptor which receptor is operatively connected to a non-invasive monitoring device, preferably the body part which is mimicked is a finger. In one embodiment there is one chamber, while in another there are two chambers.
In another embodiment, each chamber is filled with an O-cellulose material which mimics light scattering properties of tissue, preferably each chamber is filled with a gel material containing Amaranth and sodium benzoate and holding light scattering and reflective particles which mimic the light scattering properties of tissue. In another embodiment, the material which fills each chamber is fluid free. In yet another embodiment, the reflective particles comprise Teflon-PTFE, Titanium Dioxide (TiO2) or are Polystyrene nanospheres.
In yet another embodiment, the light scattering and reflecting material of the member is Teflon-PTFE, preferably the configuration of the member where in the configuration of the member to be reproducibly received, comprises a stabilizing member extending from the chamber portion to reversibly urge other surfaces of the member into contact with the measuring receptor, preferably the stabilizing member is as depicted in FIG. 9.
In another aspect according the present invention, there is provided a method of transferring algorithms from one spectral instrument to another comprising the steps of:
measuring a spectral response of a member in a first spectral instrument;
measuring a spectral response of the member in a second spectral instrument; determining any difference in measurements from the first instrument and second instrument; and
modifying the algorithms of the instruments to account for any difference, wherein the member of the method mimics the absorbance spectrum of a body part and includes the spectral components of blood analytes comprising a light scattering and reflecting material, which member has a chamber portion comprising one or more chambers, said member configured to be reproducibly received in a measuring receptor, which receptor is operatively connected to a non-invasive monitoring device, preferably the body part which is mimicked is a finger. In one embodiment of the method, there is one chamber, while in another there are two chambers.
In another embodiment of the method, each chamber is filled with an O-cellulose material which mimics slight scattering properties of tissue, preferably each chamber is filled with a gel material containing Amaranth and sodium benzoate and holding light scattering and reflective particles which mimic the light scattering properties of tissue. In another embodiment, the material which fills each chamber is fluid free. In yet another embodiment, the reflective particles comprise Teflon-PTFE, Titanium Dioxide (TiO2) or are Polystyrene nanospheres.
In yet another embodiment of the method, the light scattering and reflecting material of the member is Teflon-PTFE, preferably the configuration of the member wherein the configuration of the member to be reproducibly received, comprises a stabilizing member extending from the chamber portion to reversibly urge other surfaces of the member into contact with the measuring receptor, preferably the stabilizing member is as depicted in FIG. 9.
The invention in another embodiment provides a method for mimicking the absorbance spectrum of a body part which includes the spectral components of blood analytes. The method comprises inserting a member in a measuring device which is operatively connected to a non-invasive monitoring device; taking measurements with the device and comparing the results with those obtained from a body part of subject which the member is intended to mimic, wherein the member is comprised of a light scattering and reflecting material, which member has a chamber portion comprising one or more chambers, and the member is configured to be reproducibly received in the measuring receptor.
According to one embodiment of this method, the member of the method mimics the absorbance spectrum of a body part and includes the spectral components of blood analytes comprising a light scattering and reflecting material, which member has a chamber portion comprising one or more chambers, said member configured to be reproducibly received in a measuring receptor which receptor is operatively connected to a non-invasive monitoring device, preferably the body part which is mimicked is a finger. In one embodiment of the method, there is one chamber, while in another there are two chambers.
In another embodiment of the method, each chamber is filled with an O-cellulose material which mimics light scattering properties of tissue, preferably each chamber is filled with a gel material containing Amaranth and sodium benzoate and holding light scattering and reflective particles which mimic the light scattering properties of tissue. In another embodiment, the material which fills each chamber is fluid free. In yet another embodiment, the reflective particles comprise Teflon-PTFE, Titanium Dioxide (TiO2) or are Polystyrene nanospheres.
In yet another embodiment of the method, the light scattering and reflecting material of the member is Teflon-PTFE, preferably the configuration of the member wherein the configuration of the member to be reproducibly received, comprises a stabilizing member extending from the chamber portion to reversibly urge other surfaces of the member into contact with the measuring receptor, preferably the stabilizing member is as depicted in FIG. 9.
Other features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples while indicating preferred embodiments of the invention are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.